title: Isolation and characterization of carbendazim-degrading Rhodococcus erythropolis djl-11.
abstract: Carbendazim (methyl 1H-benzimidazol-2-yl carbamate) is one of the most widely used fungicides in agriculture worldwide, but has been reported to have adverse effects on animal health and ecosystem function. A highly efficient carbendazim-degrading bacterium (strain dj1-11) was isolated from carbendazim-contaminated soil samples via enrichment culture. Strain dj1-11 was identified as Rhodococcus erythropolis based on morphological, physiological and biochemical characters, including sequence analysis of the 16S rRNA gene. In vitro degradation of carbendazim (1000 mg·L(-1)) by dj1-11 in minimal salts medium (MSM) was highly efficient, and with an average degradation rate of 333.33 mg·L(-1)·d(-1) at 28°C. The optimal temperature range for carbendazim degradation by dj1-11 in MSM was 25-30°C. Whilst strain dj1-11 was capable of metabolizing cabendazim as the sole source of carbon and nitrogen, degradation was significantly (P<0.05) increased by addition of 12.5 mM NH4NO3. Changes in MSM pH (4-9), substitution of NH4NO3 with organic substrates as N and C sources or replacing Mg(2+) with Mn(2+), Zn(2+) or Fe(2+) did not significantly affect carbendazim degradation by dj1-11. During the degradation process, liquid chromatography-mass spectrometry (LC-MS) detected the metabolites 2-aminobenzimidazole and 2-hydroxybenzimidazole. A putative carbendazim-hydrolyzing esterase gene was cloned from chromosomal DNA of djl-11 and showed 99% sequence homology to the mheI carbendazim-hydrolyzing esterase gene from Nocardioides sp. SG-4G.
authors.affiliation: Shandong Provincial Key Laboratory of Applied Microbiology, Biotechnology Center of Shandong Academy of Sciences, Jinan, Shandong Province, People's Republic of China.
authors.forename: Xinjian
authors.initials: X
authors.lastname: Zhang
authors.forename: Yujie
authors.initials: Y
authors.lastname: Huang
authors.forename: Paul R
authors.initials: PR
authors.lastname: Harvey
authors.forename: Hongmei
authors.initials: H
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Ren
authors.forename: Jishun
authors.initials: J
authors.lastname: Li
authors.forename: Jianing
authors.initials: J
authors.lastname: Wang
authors.forename: Hetong
authors.initials: H
authors.lastname: Yang
mesh_terms: D001562:Benzimidazoles / Q000378:metabolism*; D002219:Carbamates / Q000378:metabolism*; D004950:Esterases / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D012240:Rhodococcus / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D013696:Temperature
chemical_list: D001562:Benzimidazoles; D002219:Carbamates; D004950:Esterases; C006698:carbendazim